Patients with supratentorial cerebral infarction frequently show depressed metabolic activity in the contralateral cerebellar hemisphere which is known as crossed cerebellar diaschtsisfCt.D). In order to investigate the relationship between this
phenomenon and the characteristics of the supratentorial lesion, we retrospectively evaluated the findings of 99mTc-HMPAO single photon emission computed tomography(SPECT) in 26 patients with a single supratentorial infarction lesion. A cerebellar asymmetry
index (AIcbll), percent difference between both cerebellar hemispherestzx'Scbll],SPECT volume deficit (SVD), and magnetic resonance volume deficit (MVD) were quantitated. A CCD, defined as AIcbll >12%, was observed in 12 of the 26 patients (46.2%). No correlation was found between the ~%cbll and duration of disease, SVD, or MVD. SVD and MVD values showed no significant difference between CCD positive and negative groups (71+47ml \IS. 70+68ml and 90+84ml \IS. 67+77ml,
respectively). Patients with frontoparietal lobe or deep middle cerebral artery territory infarctions showed a significantly higher incidence of CCD and lower ~%cbll values. Patients with severe hemiparesis had a higher incidence of CCD and lower ~%cbll values than those with milder or no hemiparesis (incidence, 5/5 \IS. 6/18, p=0.008; ~ %cbll,-21. 4+3.8% \IS -8. 3±11. 1%, p=O. 014). None of the 12 patients with CCD showed clinical signs of cerebellar dysfunction. In conclusion, the location rather than the extent of the lesion appears to be the major determinant for the occurrence and magnitude of CCD in stroke patients.